Pancreatic cancer is one of the most aggressive malignancies. In order to change its devastating prognosis, a novel therapeutic approach must be developed. The conditionally replicative adenovirus (CRAd) is one such promising therapeutic modality for pancreatic cancer. CRAd clinical trials to date have established the safety of these agents and identified their current limitations, and our laboratory is developing safer and more potent CRAds for therapeutic use. In this proposal, we plan to develop of a new generation pancreatic cancer CRAds with superior therapeutic potency and disease selectivity by exploiting the specific molecular features of this disease itself. We have developed new generation vector modifications which can provide a different level of transduction efficiency, and recent advancements in pancreatic cancer molecular biology have identified several target-worthy molecular features. The CRAds engineered for better potency and target specificity will be outfitted with anti-tumor effectors modifying pancreatic cancer tumor environment. New vectors will be tested not only with mouse subcutaneous and orthotopic xenograft models but also with models showing close relevance to human clinical situations. A hamster syngeneic pancreatic cancer model which allows human adenoviral replication will provide deeper insight into CRAd biology. The CRAd function analysis based on tissue slice technology permits us to evaluate CRAds in patient materials. These assessments will be further strengthened by the non-invasive viral replication monitoring capability we have developed. The development and analysis of next-generation CRAds will precede a clinically meaningful and novel therapy for pancreatic cancer.